This invention relates generally to apparatus for use with windows and specifically for use with windows such as a casement window having a sash which is adapted to be swung about an upright axis between closed and open positions.
Modern casement windows usually are associated with a reversible rotary actuator which may be used to open and close the window sash. The actuator may be in the form of a hand crank adapted to be turned in one direction to open the sash and in the opposite direction to close the sash. Alternatively, the actuator may be a reversible electric motor which is associated with the sash in the manner disclosed in Lense U.S. Pat. No. 4,553,656.
A casement window usually is equipped with one or more latches for locking the sash in its closed position. While the latch may be power-operated as disclosed in Lense U.S. Pat. No. 4,703,960, the latch more conventionally is operated manually. If the latch is locked, it must be unlocked before the sash can be opened and then must be re-locked to secure the sash after the latter has been closed. In prior windows with manually operable latches, two separate operations are necessary in order to unlock and open the sash and then two more separate operations are required to close and lock the sash. In some cases, the sash may be fully closed but inadvertently left in an unlocked condition.
Vetter et al U.S. Pat. No. 4,497,135 discloses mechanism for automatically unlocking and opening a sash and for automatically closing and locking the sash. That mechanism, however, is relatively complex and requires a motor, planetary gearing driven by the motor and a trigger for sensing the position of the sash.